Alternators for mobile use, particularly for installation in automotive vehicles, provides three-phase output current which is rectified by semiconductor diodes. The semiconductor diodes usually are constructed in form of diode plates, such as chips, which are secured to a base structure which must be so designed that it can carry away heat generated during operation of the diode.
It has previously been proposed to use cooling fins or cooling plates in combination with semiconductor rectifiers in form of sheet metal elements which are perpendicular to the axis of rotation of the generator. Usually, these cooling plates are sector-shaped--when viewed in axial direction with respect to the alternator--and bent over at their outer edge to form a flange or similar structure to increase the surface from which heat can be radiated. For high-power installations, housings are provided for the diodes which are cup-shaped or pot-shaped, the semiconductor chips being soldered to the bottom of the housing, and electrically connected at the outer side to a connecting head pin or wire. The space between the pin or wire and the diode is closed off by a casting compound. Such diodes then can be fitted into holes punched into the cooling plates which are installed in the alternator. During punching, the holes are so arranged that they have a projecting ring or burr or flange-like extension, which permits fitting the cup-shaped housings of the diodes by a press or interference fit.